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Item Characterisation of fatigue delamination growth in plain woven hybrid laminated composites subjected to Mode-I loading(Elsevier B.V., 2024) Suman, M.L.J.; Murigendrappa, S.M.; Kattimani, S.Effect of similar and dissimilar crack plane interface configuration on fatigue delamination growth in plain woven hybrid composite laminates under Mode-I has been investigated. Constant displacement amplitude fatigue testing with displacement ratio of 0.1 was carried out on 3 configurations of plain woven glass/carbon epoxy composite laminates. A power law like fit between recorded delamination length and corresponding cycle was used to predict crack length for each of the cycle. Delamination growth rate,da/dN is computed by differentiating the expression of power-law like fit. The obtained crack growth rate for each of the specimens were plotted with respect to two normalised functions, G^Imax=GImax(a)/GIR(a) where GImax is maximum mode-I energy release rate and GIR(a) is the interlaminar fracture toughness resistance and ΔG^Ieff=G^Imax-G^Imin2 as crack driving parameters computed on the basis of Modified Beam Theory (MBT) and Valvo's mode partition method (MPV) are used in Paris relation to quantify delamination propagation. It is observed that the exponent values predicted by MBT method for G^Imax is lower as compared to ΔG^Ieff. Whereas, exponent values predicted for G^Imax is higher as compared to ΔG^Ieff predicted by MPV method. The higher the exponent value, the higher is the sensitivity of the model leading to uncertainties in the crack growth prediction. Also, it is to be noted that cyclic loading effect is when both GImax and GImin is considered, the use of ΔG^Ieff as crack driving parameter to quantify delamination propagation is justified. Secondly, MBT method does not account for the mode-mixity arising due to hybrid material configuration as in the case of Local Symmetry Fatigue (LSF) and Asymmetry Fatigue (ASF) specimens. Hence, results in higher exponent as compared to MPV method. On the other side, the G^Imax and ΔG^Ieff computed on the basis of MPV method is the pure Mode-I component deduced from the total energy release rate of mode-mixity. The equations of curve fitting is very much the same for Simple Symmetry Fatigue (SSF) specimens indicating that MBT and MPV methods predict pure Mode-I behaviour for symmetric configuration for delamination growth under fatigue Mode-I loading. From the composite laminate configuration point of view, LSF specimens have higher exponents as compared to ASF and SSF specimens indicating, local symmetry configuration laminates are highly sensitive to the small uncertainties and results in unstable crack growth. Comparison of results of all hybrid composite laminates shows that the normalised functions of G^Imax and ΔG^Ieff as crack driving parameters computed on the basis of MPV method is able to capture the effect of interlayers and stacking effect on the delamination growth in hybrid plain woven composites in fatigue loading and MPV method is found to be not sensitive to G^Imax and ΔG^Ieff for displacement ratio of 0.1. © 2023 Elsevier LtdItem Analysis of UNS S31603 ferrous joint made by rotary friction welding(Springer, 2024) Senthil Murugan, S.; Girisankar, S.; Devanathan, C.; Kattimani, S.This study delves into the effects of employing low friction pressure and high axial penetration during the fabrication of friction-welded joints using UNS S31603 stainless steel. The experiments were conducted using a continuous-drive rotary friction welding machine. Crucially, the research showcases the feasibility of creating robust welds in the metal, surpassing the strength of the parent metal. The resulting weld interfaces were remarkably narrow and well-defined. The mechanical properties of the welded joints, including tensile strength, yield strength, microhardness, impact toughness, and bending/flexural strength, were meticulously evaluated following ASTM standards. The findings indicate that the welded joints exhibited impressive tensile strength, approximately 803 MPa, and withstood a peak load of 52.0 kN. Additionally, these joints demonstrated a maximum elongation of 15.3% and a yield strength of 714.0 MPa. When subjected to bending conditions, similar joints made of UNS S31603 withstood loads of up to 19.0 kN before experiencing crack propagation. Ductility was observed in the fracture mode within the weld region, characterized by the formation of cup and cone necking, highlighting the joints' ductile behaviour. Furthermore, the joint efficiency was calculated to be over 100%. Utilizing these specific parameters, this method resulted in a maximum axial shortening or material loss of approximately 14 mm. © Indian Academy of Sciences 2024.